1. Field of the Invention
The present invention pertains to methods of printing. More specifically, it pertains to an improved method of printing especially suitable for automatic printers with multiple printing stations.
2. Description of the Prior Art
The printing of paper textiles and other materials has been done, of course, in many ways over the centuries. In recent decades, the printing of paper posters and prints and textile articles such as blouses and shirts, with a myriad of designs, has become very popular. In such methods, the article to be printed in typically mounted on some sort of platen by which it is brought into contact with a mesh screen on which a particular print pattern is disposed. Some type of ink dispensing device is engaged with the screen and ink dispensed through the pattern for transfer to the article.
In recent years, printing of textile articles such as shirts and blouses has been done on a machine referred to as an automatic textile printer. These automatic textile printers usually have a frame about which is supported, perhaps on radial arms, a plurality of printing head each one of which may be capable of supporting a printing screen for engagement by an ink dispensing device. The frame of the automatic textile printer also supports a platen assembly which has a number of platens which are sequentially moveable into registration with usually adjacent ones of the printing heads. Typically, there are two more platens than the number of printing heads so that a textile article may be simultaneously placed on one and removed from another without interference from components at the printing heads.
In a typical method, a textile article is placed on a platen and the platen is moved into registration with one of the printing heads. After registration, the platen and textile article are brought into contact with a printing screen and a pattern is applied to the textile article by engaging the printing screen with an ink dispensing device after which the platen and textile article are separated from the printing screen.
If a design of more than one color is to be applied to the textile article, the platen and textile article may be moved into registration with another printing head, brought into contact with another printing screen supported thereby and printed by an ink dispensing device associated therewith. This process may continue to additional printing heads for additional colors, some of these automatic textile printers being designed with as many as twenty printing stations for application of ten colors. For a ten color machine, ten printing heads would be provided and the platen assembly would typically be provided with twelve platens, ten for registration with printing heads, one for mounting of an article to be printed and one for removing an article on which printing has been completed. Thus, an article such as a shirt may be placed on the first platen and printed at the first printing head while another shirt is being placed on the next platen. Of course, this process can continue so than ten shirts are being printed with different colors at the same time.
One of the problems in printing an article with several colors is allowing for the ink deposited at one printing station to dry 2 "or cure" prior to printing another color on the article. In some cases, this problem has been solved by placing a heating device at adjacent print heads so that after an article is printed at one print head it moves to the adjacent print head for drying and then a third print head for the application of another color. However, if a textile article is dried at alternate printing heads it cannot be printed with another color. Thus, the number of colors capable of being applied to the shirt would be reduced. For example, with a ten head automatic textile printer, in which every other head were provided with a drying device, only five colors could be applied. Solutions to these problems are needed. Furthermore, instead of purchasing a five or six color printer for $25,000 the operator may have to purchase a ten color printer for $50,000.
Many printing machines use a pivotable printing head. When the print head pivots upwardly away from the platen, heat is rapidly dissipated away from the printing screen. These pivoting head printing machines do not require shielding to protect the printing screen from heat. Unfortunately, such pivoting head printing machines require complex mechanisms to suitably pivot the printing head. These complex mechanisms can lead to a lack of printing accuracy, extra expense, and more repair. However, if the printing head does not pivot, then any application of heat can damage the printing screen. As such, a need has developed for the use of a non-pivoting head which can avoid the problems associated with the damage to the printing screen and the drying of the ink caused by the application of heat.